JP2003001638A - Method for producing polyimide molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially inexpensively produce a tubular polyimide molding which is used in an electrophotographic device such as a laser beam printer and a facimile. SOLUTION: In a method for producing the tubular polyimide molding, a polyimide precursor solution is packed/passed in/through a tubular space formed between an inner mold and an outer mold, at least one of the inner mold and the outer mold is formed from a gas permeable material, and a liquid curing the polyimide precursor chemically is made to seep from the mold formed from the gas permeable material into the space filled tubularly with the solution. The tubular polyimide molding can be produced at low costs in high productivity so that the molding can be provided inexpensively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tubular molded body made of a polyimide resin and a molding die for manufacturing the tubular molded body.

[0002]

2. Description of the Related Art Polyimide resins have excellent heat resistance, dimensional stability, mechanical strength and chemical stability, and are used in various applications such as flexible printed circuit boards and heat resistant wire insulation materials. Further, the tubular formed body is applied to a heat fixing belt, an intermediate transfer belt, etc. in an electrophotographic apparatus such as a copying machine or a laser beam printer. Hereinafter, the heat fixing belt of the electrophotographic apparatus will be described as an example.

Conventionally, as a fixing device for an electrophotographic apparatus,
The heating roller system was common. However, in recent years, a method using a tubular polyimide molding instead of the heating roller method has attracted attention. In this method, a heater is provided inside the thin film tubular polyimide molded body, and the toner image on the paper which is in contact with the heater is fixed via the polyimide layer. As an advantage of this fixing device, since the paper is in contact with the heater through the thin film tubular polyimide molded body, it is possible to reduce the preheating time and electric power as compared with the heating roller system in which the roller has to be heated,
The point is that the device becomes ready for use immediately after the power is turned on. Further, the required heat capacity of the heater is smaller than that of the heating roller system, and this is a technique that generally leads to a reduction in power consumption.

Conventionally, tubular polyimide moldings have been manufactured by the following methods, which are roughly classified into an inner coating method and an outer coating method.

In the internal coating method, a liquid raw material is applied to the inner surface of a cylindrical molded tube, and then the solvent is removed to some extent by a method such as heating or depressurization, and a semi-dried coating film exhibits self-supporting property. In this method, the coating film is peeled off from the molded tube, and the molded tube for imidization is attached to the outside to perform heating and imidization.

On the other hand, the external coating method is a method in which a liquid raw material is applied to the outer surface of a cylindrical molded tube, and drying and imidization are performed on the same molded tube.

The most difficult step in any of the methods is to allow the coating film to exhibit self-supporting properties while maintaining the thickness of the coating film. In the past, the solvent was removed by heating to cause the coating film to exhibit self-supporting properties. However, when the coating film is heated, the viscosity of the coating film is significantly reduced and liquid sagging occurs, resulting in uneven thickness of the belt. To prevent this, Japanese Patent Laid-Open No. 5-77252 discloses a method of preventing liquid sagging by heating a cylindrical molded tube while rotating it at high speed. Further, in Japanese Patent Laid-Open No. 2000-263568, a polyimide precursor solution is sprayed on the inner surface of a cylindrical molded tube that is rotating at a speed of substantially no centrifugal force, and the molded tube is heated and dried while rotating. Techniques are disclosed.

However, the above-mentioned means have a drawback that the apparatus required for the drying step is very expensive and the productivity is extremely low because continuous steps cannot be taken. Therefore, the conventional method for producing a tubular polyimide molded body is extremely expensive, and therefore the tubular polyimide molded body is extremely expensive.

[0009]

The present invention was developed as a result of earnest research on a process of exhibiting self-supporting property in a coating film while keeping the thickness of the coating film, which is extremely low in cost and high in cost. It is an object of the present invention to provide a method for producing a tubular polyimide molding having productivity.

[0010]

As a result of studies, the following invention for achieving the above object was completed.

That is, the present invention is a method for producing a polyimide molded body, which comprises a step of introducing a polyimide precursor into a space in a molding die and chemically curing at least a part of the polyimide precursor in the space. At least a part of the wall surface of the space is a wall surface made of a breathable material, and a liquid that chemically cures the polyimide precursor is exuded from the wall surface made of the breathable material and introduced into the polyimide precursor. And a method for producing a polyimide molded body.

The present invention also provides a method for producing a tubular polyimide molded body, which comprises the steps of introducing a polyimide precursor into a space inside a mold and chemically curing at least a part of the polyimide precursor within the space. At least a part of the wall surface of the space is a wall surface made of a gas permeable material, and a liquid that chemically cures the polyimide precursor is exuded from the wall surface made of the gas permeable material and introduced into the polyimide precursor. The method for producing a tubular polyimide molded body is characterized by:

In one embodiment of the above invention, the molding die is a male and female mating mold of an outer mold and an inner mold, and a tube between the outer mold and the inner mold obtained by mating the mating molds. The polyimide precursor is introduced into the space.

The liquid for chemically curing the polyimide precursor preferably contains at least either an aliphatic acid anhydride or an aromatic acid anhydride.

In another aspect, the present invention provides the following mold.

That is, a molding die for producing a polyimide molded body, wherein a polyimide precursor is introduced into a space inside the mold, and at least a part of the polyimide precursor is chemically cured in the space. At least part of the wall of
Provided is a molding die for producing a polyimide molded body, which is a wall surface made of a breathable material.

Further, in one embodiment, the molding die is a male and female mating die of an outer die and an inner die, and when the mating die is mated, the polyimide is placed between the outer die and the inner die. It is characterized in that a cylindrical space for introducing the precursor is formed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A general process for producing a polyimide molded body is roughly divided into the following four steps. That is,
(1) a step of polymerizing a polyamic acid in an organic solvent to prepare an organic solvent solution of the polyamic acid (in this specification, this solution is referred to as a polyimide precursor); Filling or casting or coating on a support in a space in a molding die so as to have a substantially final shaping shape, (3) until the filled or cast or coated polyimide precursor exhibits self-supporting property. A step of drying and / or curing, and a step (4) of completing the organic solvent drying and imidization. Incidentally, the curing in the step (3) refers to an imidization reaction, and as a method of promoting the imidization reaction, a thermal method and a chemical method are well known.

In the production method of the present invention, the above (2)
In the step of (2), a method of introducing and filling the polyimide precursor into the space inside the mold is adopted. The curing in the step (3) employs a method of curing at least a part of the polyimide precursor mainly by a chemical method.

The term "curing at least a part of the polyimide precursor by a chemical method" means imidizing all or part of the polyamic acid units contained in the polyimide precursor, and molding It does not mean local curing (imidization) of the polyimide precursor filled in the mold.

Further, in the present invention, a liquid that chemically cures the polyimide precursor is introduced into the polyimide precursor by being exuded from the wall surface made of a gas permeable material provided on the wall surface of the space in the mold. It is characterized by

The liquid for chemically curing the polyimide precursor is typically a dehydrating ring-closing agent for polyamic acid, and its main components are aliphatic acid anhydride, aromatic acid anhydride, N, N. '-Dialkylcarbodiimide, lower aliphatic halide, halogenated lower aliphatic acid anhydride, arylsulfonic acid dihalide, thionyl halide or a mixture of two or more thereof can be preferably used. Among them, aliphatic acid anhydrides and aromatic acid anhydrides are particularly preferable because they work well. These compounds are solventless or dissolved in an organic solvent to prepare a liquid that chemically cures the polyimide precursor.

When a catalyst acts on the curing reaction of the polyimide precursor, the catalyst may be added to the liquid that chemically cures the polyimide precursor. Another method is to add a catalyst to the polyimide precursor in advance. Also, these methods may be used together.

As the catalyst, aliphatic tertiary amine, aromatic tertiary amine, heterocyclic tertiary amine and the like are used. Among them, isoquinoline, β-picoline, and pyridine work particularly well.

The wall surface made of a gas permeable material provided on the wall surface of the space in the molding die for exuding the liquid that chemically cures the polyimide precursor is the pore diameter of the surface.
1 μm or more and 100 μm or less, preferably 3 μm or more 50
Desirably it is less than μm. When the pore size is small, the air permeability (liquid permeability) is deteriorated, and it may be difficult to exude the liquid that chemically cures the polyimide precursor from the fine pores. On the other hand, if the pore size is large, the surface properties of the polyimide molded body may be deteriorated, or the polyimide molded body may be difficult to peel off due to the anchor effect.

Further, if foreign matter is present in the liquid that chemically cures the polyimide precursor, the air permeable material may be clogged. Therefore, the liquid is filtered with a filter having a finer opening than at least the pore diameter of the air permeable material. It is preferable to remove foreign substances by filtration.

The step of exuding the liquid that chemically cures the polyimide precursor is carried out in a state in which the polyimide precursor is filled and fixed in the space inside the molding die, as well as the polyimide precursor in the molding die. You may go while moving in space. Simultaneously with or after these operations, heating the polyimide precursor may be appropriately selected. The heating temperature at this time is preferably not higher than the boiling point of the solvent, and heating in the range of substantially 30 to 150 ° C. is preferable.

At least a part of the polyimide precursor that has undergone the above steps is chemically cured in the molding die.
When the curing is not completed, the operation for further curing may be performed in the molding die as it is, or may be detached from the molding die and fixed to another mold. In order to efficiently dry the organic solvent in the polyimide precursor, a method of removing the organic solvent from the molding die, fixing it in another mold and heating it is preferable.

More specifically, a preferable mold for producing a tubular polyimide molded body will be described in more detail. A mold having an internal space for introducing a polyimide precursor is a male-male mold of an outer mold and an inner mold. Preferably the outer mold is cylindrical and the inner mold is cylindrical. The inner diameter of the outer mold is made larger than the outer diameter of the inner mold so that the space obtained between the outer mold and the inner mold when the molds are matched becomes a cylindrical space. A polyimide precursor is introduced into this cylindrical space, and a liquid for curing the polyimide precursor is introduced through the wall surface made of a gas permeable material provided in the outer mold, the inner mold, or both during or after the introduction. FIG. 1 shows a mold used in the specific example described here and a state in which the mold is filled with a polyimide precursor.

Although not shown, the molding die may be provided with an air vent hole for introducing the polyimide precursor or a liquid pressure adjusting mechanism for hardening the polyimide precursor, if necessary.

After partially curing the polyimide precursor and obtaining self-supporting property, the polyimide precursor is once removed from the molding die, the tubular body is fitted in a cylindrical mold, and then the curing is completed and the solvent is dried. The method is a preferred embodiment because of high production efficiency.

A method of heating is preferably used for completion of curing and drying. The temperature condition at this time is not particularly limited, but the solvent is volatilized to some extent at a temperature equal to or lower than the boiling point of the solvent, and then the temperature is further raised to a high temperature of about 200 ° C. to 500 ° C. As an example, a method of causing almost complete volatilization and further progress of imidization can be mentioned.

After that, the resin is removed from the cylindrical mold to obtain the desired tubular polyimide molding.
As the cylindrical mold, the inner mold of the original molding mold may be used as it is, and in that case, the step of temporarily removing the molded body can be omitted.

The tubular polyimide molded body in the present invention means a seamless hollow molded body mainly made of polyimide, and the manufacturing method and the manufacturing apparatus of the present invention may be large or small in diameter or thickness. Therefore, it can be applied to a large diameter one often called a belt and a small diameter one often called a tube.

As the breathable material according to the present invention, a material having a three-dimensional network structure, a metal body having a through hole, or the like can be used regardless of the type of material as long as it has breathability. Among them, especially fine metal particles are pressure-bonded and / or
Alternatively, the porous metal, the air-permeable ceramic, the air-permeable carbon, and the air-permeable heat-resistant glass obtained by firing give good results in the surface properties of the obtained molded product.
Further, physical treatment such as polishing or sandblasting may be appropriately adopted for the surface of the breathable material. Also,
Surface treatment such as glass coating or ceramic coating may be performed as long as the air permeability of the air permeable material can be secured. Furthermore, for the purpose of assisting the peelability from the mold,
A release agent may be used on the surface of the mold.

In the method for producing a tubular polyimide molding according to the present invention, the polyimide precursor is not particularly limited as long as it is a solution containing a polyamic acid, and other components.
In order to control the properties of the finally obtained tubular polyimide molded body, various materials can be introduced regardless of organic or inorganic materials. For example, for the purpose of controlling the resistance value, a method of mixing an appropriate amount of conductive inorganic powder such as carbon black in a resin is most effective. In addition to carbon black, small-sized metal particles, metal oxide particles, titanium oxide, various inorganic particles, and whiskers coated with a conductive substance such as a metal oxide can provide similar effects. . Furthermore, it is also possible to add an ion conductive substance such as LiCl. For the purpose of controlling the thermal conductivity, for example, aluminum nitride, boron nitride, alumina, silicon carbide, silicon, silica, graphite and the like can be mentioned. Among them, boron nitride is preferable because it has a high heat conduction function, exhibits a releasing effect, is chemically stable, and is harmless.

In the method for producing a tubular polyimide molding according to the present invention, the polyamic acid is obtained by polymerizing an aromatic tetracarboxylic acid component and a diamine component in an organic polar solvent.

The aromatic tetracarboxylic acid component is not particularly limited, and examples thereof include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1, 2,3,4-Cyclobutane tetracarboxylic acid, 1,2,3,4-cyclopentane tetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 3,5,6-tricarboxy Norbonane-2-acetic acid dianhydride, 2,3,4
5-tetrahydrofuran tetracarboxylic dianhydride, 5
-(2,5-Dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, bicyclo [2,2,2] -oct-7-ene-2,
Aliphatic or alicyclic tetracarboxylic dianhydride such as 3,5,6-tetracarboxylic dianhydride; pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride 1,3 ', 4,4'-biphenylsulfone tetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic acid dianhydride, 2,3,6,7-
Naphthalenetetracarboxylic dianhydride, 3,3 ', 4
4'-biphenyl ether tetracarboxylic dianhydride,
3,3 ', 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3', 4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4
-Furan tetracarboxylic acid dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride , 4, 4'-
Bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4
4'-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-
Phenylene-bis (triphenylphthalic acid) dianhydride,
m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylether dianhydride, bis (triphenylphthalic acid)
Aromatic tetracarboxylic dianhydrides such as -4,4'-diphenylmethane dianhydride; 1,3,3a, 4,5,9b-
Hexahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3
3a, 4,5,9b-hexahydro-5-methyl-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Naphtho [1,2-c] furan-1,3-dione, 1,
3,3a, 4,5,9b-hexahydro-8-methyl-
Examples thereof include aliphatic tetracarboxylic dianhydrides having an aromatic ring such as 5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione. it can. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

The diamine to be used next is not particularly limited as long as it is a diamine. For example, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4, 4'-diaminodiphenyl ether, 4,4 '
-Diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene,
3,3-dimethyl-4,4'-diaminobiphenyl, 5
-Amino-1- (4'-aminophenyl) -1,3,3
-Trimethylindane, 6-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 4,
4'-diaminobenzanilide, 3,5-diamino-
3'-trifluoromethylbenzanilide, 3,5-diamino-4'-trifluoromethylbenzanilide,
3,4'-diaminodiphenyl ether, 2,7-diaminofluorene, 2,2-bis (4-aminophenyl)
Hexafluoropropane, 4,4'-methylene-bis (2-chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4 ′ -Diamino-5,5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 2,2 -Bis [4-
(4-Aminophenoxy) phenyl] propane, 2,2
-Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) -biphenyl, 1,3'- Bis (4-aminophenoxy) benzene, 9,9-bis (4-aminophenyl)
Fluorene, 4,4 '-(p-phenylene isopropylidene) bisaniline, 4,4'-(m-phenylene isopropylidene) bisaniline, 2,2'-bis [4-
(4-Amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-bis [4
Aromatic diamine such as-(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl;
Aromatic diamine having two amino groups bonded to an aromatic ring such as diaminotetraphenylthiophene and a hetero atom other than the nitrogen atom of the amino group; 1,1-metaxylylenediamine, 1,3-propanediamine, Tetramethylenediamine, pentamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7 -Methanoin danylene dimethylene diamine, tricyclo [6,6
2,1,0 ^2.7 ] -undecylenedimethyldiamine,
Examples thereof include aliphatic diamines such as 4,4′-methylenebis (cyclohexylamine) and alicyclic diamines. These diamine compounds may be used alone or in combination of two or more. An aromatic diamine is preferably used as the diamine, but the diamine is not particularly limited.

Examples of the organic polar solvent used in the reaction for producing the polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide such as N, N-dimethylformamide and N, N-diethylformamide. System solvents, acetamide-based solvents such as N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone,
A pyrrolidone-based solvent such as N-vinyl-2-pyrrolidone,
Phenol-based solvents such as phenol, o-, m- or p-cresol, xylenol, halogenated phenol and catechol, ether-based solvents such as tetrahydrofuran, dioxane and dioxolane, alcohol-based solvents such as methanol, ethanol and butanol, butyl cellosolve and the like. Cellosolve system, hexamethylphosphoramide, γ-butyrolactone and the like can be mentioned, and it is desirable to use these alone or as a mixture, and aromatic hydrocarbons such as xylene and toluene can also be used. The solvent is not particularly limited as long as it dissolves the polyamic acid. Also, water accelerates the decomposition of the polyamic acid and must be removed as much as possible.

Next, an example of a specific method for producing a tubular polyimide molding will be described.

Inorganic powder is added to a polyimide precursor obtained by polymerizing an aromatic tetracarboxylic acid component and a diamine component in an organic solvent, and the dry weight of the polyimide precursor is 100.
5 to 60 parts by weight is contained with respect to parts by weight. On this occasion,
It is also possible to properly select to mix an appropriate amount of a catalyst with the polyimide precursor. As a method of containing the inorganic powder, a method of mixing the inorganic powder in an organic solvent and then polymerizing the monomer in the organic solvent, an inorganic powder or a dispersion thereof in a solution in the intermediate step of the polymerization reaction or after the reaction is completed. There is a method of mixing. As a method for dispersing the inorganic powder and reducing the size of the aggregate, physical methods such as stirring with a mixer or a stirrer, parallel rolls, ultrasonic dispersion, and ball mill, and further chemical methods such as introduction of a dispersant However, the present invention is not limited to these.

The polyimide precursor obtained by the above means is introduced into a tubular space provided between the inner mold and the outer mold by a method such as casting or extrusion. Next, by exuding a liquid that chemically cures the polyimide precursor from the inner or outer mold made of a gas permeable material, the polyimide precursor is cured and converted into a tubular film having self-supporting properties. .

[0044]

EXAMPLES Next, the method for producing the tubular polyimide molded article according to the present invention will be described in detail with reference to Examples.

Example 1 1500 g of dimethylformamide (DMF) sufficiently dehydrated with a molecular sieve was placed in a vessel equipped with a stirring blade, 200 g of 4,4'-diaminodiphenyl ether was added, and the mixture was stirred until completely dissolved. did. The system was cooled to about 0 ° C., 218 g of pyromellitic dianhydride was gradually added, and the mixture was stirred well. When the viscosity of the system reached about 3 × 10 ² Pa · s, stirring was stopped and a polyimide precursor was obtained.

Next, a metal filler FT-20 manufactured by Ishihara Sangyo Kaisha, Ltd.
00 g and DMF 300 g were put in another container, stirred well, and further subjected to an ultrasonic disperser to uniformly disperse the metal filler in the dispersion. Also, in another container, 15 g of Mitsubishi Chemical's carbon black 3030B
And DMF (300 g) were added, and the mixture was stirred well and subjected to an ultrasonic disperser.

The metal filler dispersion and the carbon black dispersion obtained above were each placed in the same beaker at 9
8 g and 45 g were sampled and stirred well. Into this beaker, 300 g of the polyimide precursor obtained above was melted and further stirred. Thus, a mixed solution containing about 25 parts by weight of the metal filler and about 3 parts by weight of carbon black was obtained with respect to 100 parts by weight of the dry weight of the polyimide precursor. Further, 15 g of isoquinoline was mixed into this solution as a catalyst to prepare a polyimide precursor.

The polyimide precursor thus obtained was used as an inner mold having an inner diameter of 70 mmφ, an outer diameter of 80 mmφ, and a length of 500 mm, which was made of a gas permeable metal having an average pore diameter of 5 μm, and an inner diameter of 81.4 mmφ and an outer diameter of 90 mmφ. 500 m
It was filled in a cylindrical space having a width of 0.7 mm, an inner diameter of 80 mm and a length of 500 mm, which was obtained by inserting it into an SUS outer mold of m. After the above-mentioned cylindrical space is uniformly filled with the polyimide precursor, one end open part of the inner mold is closed, and the polyimide precursor of acetic anhydride: DMF = 5: 1 is chemically cured from the other end open part. The liquid for curing was introduced by using compressed air, so that the liquid for chemically curing the above polyimide precursor was exuded from the surface where the inner mold was in contact with the polyimide precursor. The liquid temperature at this time was 21 ° C.

After leaving for 10 minutes, the outer mold was removed, and the cylindrical film in a semi-cured state with the inner mold was placed in an oven set to 100 ° C. and heated for 10 minutes. Then, from 100 ℃ to 38
The imide conversion reaction was allowed to proceed by raising the temperature from 0 ° C to 100 ° C to 380 ° C over about 30 minutes. afterwards,
The mold was allowed to cool at room temperature, the resin was removed from the inner mold, and the target tubular polyimide molded body was obtained.

Although the tubular polyimide molded article according to the present invention has been described above, the present invention is not limited to the above-mentioned embodiment. Needless to say, it can be implemented in various modifications within the range described.

[0051]

As described above, the method for producing the tubular polyimide molded article and the molding die for producing the tubular polyimide molded article according to the present invention are, as described above, a very simple method to the polyimide precursor in the molding die. A liquid can be introduced that hardens the precursor. Therefore, the tubular polyimide molded body can be easily manufactured, and the manufacturing cost of the tubular polyimide molded body can be drastically reduced.

As described above, most of the problems existing in this type of conventional example are solved, and the effect of the present invention is remarkably large.

[Brief description of drawings]

FIG. 1 is a schematic view of an example of liquid exudation that chemically cures a polyimide precursor.

[Explanation of symbols]

1 Inner mold made of breathable mold 2 Polyimide precursor 3 External type 4 Liquid that chemically cures polyimide precursors

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 79:08 C08L 79:08 AF term (reference) 4F071 AA60 AB03 AB06 AC09 AC19 AD02 AE02 BB01 BC05 4F203 AA40 AG08 AK01 DA12 DB01 DC02 DC23 DK01 DL14 DM03 DM08 DM23 4F204 AA40 AB03 AG08 AH33 AJ11 EA03 EA04 EB01 EF02 EF23 EK17 EK24

Claims (6)

[Claims] 1. A method for producing a polyimide molded body, comprising a step of introducing a polyimide precursor into a space in a molding die and chemically curing at least a part of the polyimide precursor in the space, At least a part of the wall surface of the space is a wall surface made of a breathable material, and a liquid that chemically cures the polyimide precursor is exuded from the wall surface made of the breathable material and introduced into the polyimide precursor. A method for producing a polyimide molded body. 2. A method for producing a tubular polyimide molded body, which comprises the step of introducing a polyimide precursor into a space in a molding die and chemically curing at least a part of the polyimide precursor in the space, At least a part of the wall surface of the space is a wall surface made of a gas permeable material, and a liquid for chemically curing the polyimide precursor is exuded from the wall surface made of the gas permeable material and introduced into the polyimide precursor. And a method for producing a tubular polyimide molded body. 3. The polyimide precursor is a male and female mating mold of an outer mold and an inner mold, and the polyimide precursor is provided in a cylindrical space between the outer mold and the inner mold obtained by mating the mating molds. The method for producing a tubular polyimide molded article according to claim 2, wherein a body is introduced. 4. The liquid that chemically cures the polyimide precursor contains at least one of an aliphatic acid anhydride and an aromatic acid anhydride.
4. The method for producing a polyimide molded body according to any one of 3 to 3. 5. A molding die for producing a polyimide molded body, wherein a polyimide precursor is introduced into a space in the mold, and at least a part of the polyimide precursor is chemically cured in the space. A molding die for producing a polyimide molded body, wherein at least a part of the wall surface of the above is a wall surface made of a breathable material. 6. A cylinder for introducing the polyimide precursor between the outer mold and the inner mold when the molding mold is a male and female mating mold including an outer mold and an inner mold. A mold for producing a polyimide molded body according to claim 5, wherein a shaped space is formed.